The so-called "Mozart effect" - an increase in certain measures of intelligence after listening to the music of Mozart - has not been confirmed by recent experiments, according to a report published in the Journal of Psychological Science.

Mozart: Music became big business

"We conclude that there is little evidence to support it," say scientists from Appalachian State University in the US.

The effect was first reported in 1993 by researchers at the University of California, and again by the same team two years later.

They based their conclusions on two experiments involving 36 students that showed a significant improvement in IQ tests. They listened to samples of Mozart's Sonata for Two Pianos in D Major. The drawback with the increase was that it did not last long - only 15 minutes.

Thriving industry

The researchers suggested that the intelligence boost was somehow related to something unique in Mozart's music. Since then, an industry has emerged selling Mozart's and other composers' classical music as a way to increase intelligence, especially among children.

But reporting on their attempt to replicate the IQ effect, researchers from North Carolina say they cannot confirm it.

They increased the number of people tested, who listened to Schubert as well as Mozart. But apart from what they call a general good feeling after listening to the classical music, they say there was no measurable increase in intelligence.

Classical music may relieve tension and stress and help focus attention but its ability to increase intelligence is, according to this latest research, rather doubtful.